Apparatus for coring bolt holes



March 14, 1967 E. ROWLAND 3,308,513

APPARATUS FOR CORING BOLT HOLES Filed June 1, 1965 2 Sheets-Sheet lFiG.|

INVENTOR. f 8 Ill/z. TON f, ROWLAND March 14, 1967 Filed June 1, 1965 M.E. ROWLAND 3,308,513

APPARATUS FOR CORING BOLT HOLES 2 Sheets-Sheet 2 NVENTOR.

1 M1. row A. Roman/v.0

United States Patent 3,308,513 APPARATUS FOR CORING BOLT HOLES Milton E.Rowland, Long Beach, Calif., assignor to Pacific Valves, Inc., LongBeach, Calif, a corporation of California Filed June 1, 1965, Ser. No.460,181 Claims. (Cl. 22-131) This invention relates to a method ofcoring bolt holes in a steel casting, and particularly where such holesare required in a flanged part of the casting, such as a valve bodywhich is provided with flanges whereby the valve is bolted in a pipeline or the like.

An object of my invention is to provide a novel method whereby boltholes may be cored in a steel casting, which has not been heretoforeaccomplished due to the amount of contraction of the steel when goingfrom a molten to a solid state.

Another object of my invention is to provide a novel method ofsimultaneously forming bolt holes in a steel casting, and the flat spotface areas which surround the bolt hole at one end thereof.

Another object of my invention is to provide a novel method of coringbolt holes in which the core can be formed of either metal, wood, or aplastic product.

Still another object of my invention is to eliminate the presentrequirement of setting a valve in a drill press to drill the bolt holesand, subsequently, to operate the spot face tool through the drilledholes.

Still another object is to provide a method which materially decreasesthe cost of manufacture of the cast articles, and also which willprovide greater accuracy for the bolt hole spacing in the casting, andalso to accomplish a flat and smooth spot face surface. Also with mymethod the production of articles can be materially increased, since thedrilling time and setting-up time of drilling machines is entirelyeliminated.

Other objects, advantages and features of the invention may appear fromthe accompanying drawings, the subjoined detailed description and theappended claims.

In the drawing:

FIGURE 1 is a top plan view of the sand mold with various corespositioned therein.

FIGURE 2 is a plan view of half of a sand mold showing the shapedrecesses therein but without the cores.

FIGURE 3 is a perspective view of one-half of a bolt hole forming core.

FIGURE 4 is a sectional view taken on line 4-4 of FIGURE 1.

FIGURE 5 is a fragmentary sectional view taken on line 5-5 of FIGURE 1.

FIGURE 6 is a fragmentary vertical sectional view through one of thebolt holes formed by a core.

FIGURE 7 is a fragmentary vertical view of the steel casting as it isremoved from the mold.

FIGURE 8 is a view similar to FIGURE 7 but showing the flange surfacemachined to expose the bolt holes.

FIGURE 9 is a perspective view of a valve molded according to my method.

Referring more particularly to the drawing, the numeral 1 indicates asand core which has been shaped and baked so that it forms asubstantially rigid bed, into which the molten steel can be poured toproduce the cast article. The mold 1 is preferably formed in twocomplementary parts 23 which separate on what is termed a parting line4. The sand of which the mold 1 is made has certain additives which,when the sand is baked, will produce a very rigid body and one in whichthe sand will not shift about. The mold 1 has shaped recesses 5 formedtherein to produce the external shape of an article, such as the valve 6and the flanges 7 thereon. The

flanges 7 are provided with a plurality of circumferentially spaced boltholes 8, and it is these bolt holes which form the subject matter ofthis invention. Heretofore it was necessary to drill these bolt holes ina drill press, requiring many man hours of labor, and also these boltholes were not necessarily accurately spaced. In my invention these boltholes are accurately cored in the flanges 7 of the article 6 and aremolded simultaneous with the body of the article, such as the valve 6.The recesses 9 are circularly shaped to produce the flanges 7, and anadjacent recess 10 is parallel to the recess 9 for the purpose ofreceiving the bolt hole core 11. The bolt hole core 11 is formed in twocomplementary halves 12-13 and each half includes the following parts:

A peripheral rim 14 is substantially the same width as the groove 10 andcompletely fills this groove at the periphery thereof. Integral with therim 14 I provide a flange 15 which projects inwardly from the rim 14. Aplurality of circumferentially spaced bolt hole cores 16 in the shape ofshort pins project into the arcuate groove 9. The pins 16 are eachformed with a somewhat circular base 17 which form and shape the spotface 18 in one face of the flange 7 of the finished product. It will benoted that the pin 16 does not extend entirely to the outer wall of thegroove 9, but terminates before reaching this end wall to form a thinsteel covering sheet 19 over the bolt hole 8, as best shown in FIGURES 6and 7. When the surface of the flange 7 is machined to provide a smoothand accurate face, the thin metal sheet 19 will tend to guide the toolin its path and will prevent the tool from dropping into the bolt holes8, and will thus prevent chattering of the tool or damage to the flangeof the cast article.

In FIGURE 5 the bolt hole core is somewhat differently shaped than thatshown in FIGURE 4. The purpose of this core is to form the bolt holes inthe flanged portion 20 of the valve 6. The general construction of thepins, the base of the pins, etc., is the same as previously describedwith regard to the core 11. So that the cores 11 may be accuratelypositioned and aligned in the sand mold 1, I provide an outwardlyprojecting blade 21 on each of the bolt hole cores, and this blade fitsaccurately into the blowhole 22 in the mold.

Under certain casting conditions it is also possible to reverse theposition of the bolt hole core 11 so that the pins 16 thereon willextend in the opposite direction; that is, they will extend inwardlyinstead of outwardly when in position in the mold box. It is alsopossible to make the bolt hole core 11 in one circular piece instead oftwo pieces, as shown, if this should be desirable.

Having described my invention, I claim:

1. An apparatus for coring bolt holes in a steel casting during thecasting operation comprising,

a mold having cavities therein conforming to the shape of the steelarticle, including a cavity conforming to the shape of a flange on thearticle;

said mold having another cavity therein adjacent and parallel to thecavity conforming to the shape of the flange on the article,

a bolt hole core fitting into the last named cavity,

said bolt hole core including a core pin projecting into the cavityconforming to the shape of a flange on the article,

a protruding spot face base on the inner end of the bolt hole core.

2. An apparatus for coring bolt holes in a steel casting during thecasting operation comprising,

a sand mold formed in two complementary parts having cavities thereinconforming to the shape of the steel article, including a cavityconforming to the shape of a flange on the article;

said mold having another cavity therein adjacent and parallel to thecavity conforming to the shape of the flange on the article,

a bolt hole core fitting into the last named cavity formed in twocomplementary parts,

said bolt hole core including a core pin projecting into the cavityconforming to the shape of a flange on the article.

3. An apparatus for coring bolt holes in a steel casting during thecasting operation comprising,

a sand mold formed in two complementary parts having cavities thereinconforming to the shape of the steel article, including a cavityconforming to the shape of a flange on the article;

said mold having another cavity therein adjacent and parallel to thecavity conformingto the shape of the flange on the article,

a bolt hole core fitting into the last named cavity formed in twocomplementary parts,

said bolt-hole core including a core pin projecting into the cavityconforming to the shape of a flange on the article,

a protruding spot face base on the inner end of the bolt hole core.

- 4. An apparatus for coring bolt holes in a steel casting during thecasting operation comprising,

a mold having cavities therein conforming to the shape of the steelarticle, including a cavity conforming to the shape of a flange on thearticle,

said mold having another cavity therein adjacent and parallel to thecavity conforming to the shape of the flange on the article,

a bolt hole core fitting into the last named cavity,

said bolt hole core including a rim, an inwardly projecting flange, anda core pin projecting into a cavity conforming to the shape of a flangeon the article.

5. An apparatus for coring bolt holes in a steel casting during thecasting operation comprising,

a mold having cavities therein conforming to the shape of the steelarticle, including a cavity conforming to the shape of a flange on thearticle,

said mold having another cavity therein adjacent and parallel to thecavity conforming to the shape of the flange on the article,

a bolt hole core fitting into the last named cavity,

said bolt hole core including a rim, an inwardly projecting flange, anda core pin projecting into a cavity conforming to the shape of a flangeon the article,

a protruding spot face base on the inner end of the bolt hole core.

References Cited by the Examiner UNITED STATES PATENTS I. SPENCEROVERHOLSER, Primary Examiner.

E. MAR, Assistant Examiner.

1. AN APPARATUS FOR CORING BOLT HOLES IN A STEEL CASTING DURING THECASTING OPERATION COMPRISING, A MOLD HAVING CAVITIES THEREIN CONFORMINGTO THE SHAPE OF THE STEEL ARTICLE, INCLUDING A CAVITY CONFORMING TO THESHAPE OF A FLANGE ON THE ARTICLE; SAID MOLD HAVING ANOTHER CAVITYTHEREIN ADJACENT AND PARALLEL TO THE CAVITY CONFORMING TO THE SHAPE OFTHE FLANGE ON THE ARTICLE, A BOLT HOLE CORE FITTING INTO THE LAST NAMEDCAVITY, SAID BOLT HOLE CORE INCLUDING A CORE PIN PROJECTING INTO THECAVITY CONFORMING TO THE SHAPE OF A FLANGE ON THE ARTICLE, A PROTRUDINGSPOT FACE BASE ON THE INNER END OF THE BOLT HOLE CORE.